Toilet cistern



FIG. 1 is a perspective view of a toilet cistern showing our new design;

FIG. 2 is an elevated front view thereof;

FIG. 3 is an elevated left thereof;

FIG. 4 is an elevated right thereof;

FIG. 5 is an elevated rear view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is bottom plan view thereof. 

The ornamental design for a toilet cistern, as shown and described. 